The Studies On The Synthetic Methods Of Benzofuran Neolignan And 8-5' Neolignan Compounds

Benzofuran neolignans and 8-5' neolignans are widespread in nature, exhibiting a broad range of biological activities and are potent ingredients of many medicine plants. Benzofuran neolignans include 2-phenyl benzofuran neolignans and its dihydro, tetrahydro, hexhydro derivatives. In order to meet the needs for selecting the substances with biological activities and developing new drugs, this thesis aims at the studies on the syntheses of dihydrobenzofuran neolignan compounds, benzofuran neolignan compounds and 8-5' neolignan componds.First, the structure classification, physical and chemical characters and biological activities of lignan compounds were introduced in the thesis. Meanwhile, their application in pharmacology and taxonomy was also mentioned. The biological activities and the previous synthetic reports of benzofuran neolignan compounds, dihydrobenzofuran neolignan componds and 8-5' neolignan componds were also introduced briefly.Aiming at constructing dihydrobenzofuran skeleton, the synthetic routes were devised. Nine compounds (1)⁹ have been synthesized, which belong to dehydrobenzofuran neolignans and benzofuran neolignans compounds. The synthetic routes as following:1. Starting from p-hydroxybenzaldehyde and malonic acid, compound (20) was synthesized via Knoevenagel reaction, esterification reaction and Ag2O-catalyzed biomimetic oxidative coupling reaction in three steps. Compound (1), (2), (3) and (5) were synthesized from compound (20) via acetic anhydride to protect the 4-OH goup of compound (20), DDQ dehydrogen reaction, deacetyl reaction and lithium aluminium hydride reductive reaction in four steps. Compound (4) was synthesized via saponification of compound (3). Compound (6) and (7) were synthesized from compound (20) via methylized reaction and DDQ dehydrogen reaction in two steps. Compound (8) was synthesized via saponification of compound (20) in room temperature. Synthesis of compound (2) and (7) not only achieved transformation successfully from dihydrobenzofuran neolignans to benzofuran neolignans, but also offered a new method to synthesize benzofuran construction. So this synthetic route has applied value. Thereinto Ag2O-catalyzed biomimetic oxidative coupling reaction was a key step of this synthetic route.2. Starting from 3-methoxy-4-hydroxybenzaldehyde and malonic acid,...